1. Field of the Invention
The invention relates generally to devices and methods used in rooftop ventilator systems, and more particularly to hinged hold-open devices that can be used to retain the cover in multiple positions for maintenance activities.
2. Description of Related Art
In commercial ventilation systems for buildings, larges fans are mounted over vents in a roof. For example, a fan-assisted vent at a restaurant permits an exhaust to be withdrawn from the kitchen. Through this vent, grease and other cooking residue are allowed to leave the building. After a period of use, the vent and the fan become contaminated with grease. Other cooking residue also becomes adhered to the fan blades and other surfaces. Such residue can be flammable and presents a fire hazard, and can also attract undesirable microbes and illness causing bacteria, requiring occasional cleaning.
In most of these systems, a rectangular base rises above the roof vent, and the open base is covered by a rectangular lid. The lid is sometimes referred to as a shoebox lid, because is similar in construction to a cardboard shoebox, but formed from sheet metal. A large hole exists in the lid, and the fan is securely mounted to the lid. Over time the fan becomes dirty and requires cleaning and maintenance. For maintenance purposes, the lid is typically hinged to the base, allowing a worker to raise the lid and rotate the lid and fan assembly away from the base for proper access.
The problem for many workers is that the lid can be difficult to grasp, requiring the worker to lift the edges of the lid with fingers, and then rotate the heavy fan and lid assembly back into a fixed open position. Given the dangers of the fan and lid assembly inadvertently falling in either direction, it is important to place it into the desired position safely and securely. Moreover, it is also important that the maintenance worker have the flexibility to position the fan and lid into a plurality of positions.
Therefore, there is a need for a device which can be attached to the lid and fan base that serves as a replacement hinge and which allows easier and safer positioning of the lid in an open configuration when maintenance is required. The device should be simple to install and use, and it should not require any irreversible modifications to the lid itself.